Is there a way to mass-rename an object's suffix?
Not natively, no, but you can try one of these addons:


Name Panel Addon http://blenderartists.org/forum/showthread.php?272086-Addon-Item-Panel-amp-Batch-Naming-1-4 or
Batch Rename Datablocks http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Object/Batch_Rename_Datablocks